How do I find my iPhone 6 with Find My iPhone when the name changed on iCloud?

My son had his iPhone 6 stolen and it was registered on Find My iPhone. Within a day or so of the theft, my son put the phone in "lost mode" on the iCloud. About 10 days after it was stolen, while we were periodically monitoring iCloud to see if it ever got turned-on, my son changed his login name & password on iCloud. So now he has two devices (iPhone 6 & iPad) with the old name on them, with the corresponding passwords, and his iCloud account with a new name & a new password.

To add perspective on my question, even though his iPad had the old name & old password, it was located on his iCloud Find My iPhone map that had the new account name & new password. His iCloud would indicate when the iPad was turned on or off. What I'd like to find out is, since there appears to still be a linkage between his iCloud account and his iPad, would it follow that there would continue to be a linkage with his iPhone 6 (old name/old password) and his iCloud account. If the linkage continues, we would continue to monitor his iCloud in case the phone gets turned on; if not, we will of course just have to move on.

Btw, I know this is a problem most if not all people here will have no clue about. It has to be rare that someone changes their iCloud name in the midst of trying to track their lost/stolen phone. If someone is willing to do a test on their device/account it might shed light on whether my conclusion is right or wrong. Simply changing the login name on one's iCloud account without making a corresponding change on an iPhone or other device to see if the device is locatated on the Find My iPhone map. Anyway, we would appreciate any help at all with this!

The only thing you did was "change" your current iCloud/Apple ID to a different one. You've basically renamed it, although Apple states that you can't rename an Apple ID, and thus the device is still associated. It will stay associated to your account until you release it via the Find My iPhone feature online or by calling Apple and have them do it as long as you can prove your identity. At least that's my understanding.

The only thing you did was "change" your current iCloud/Apple ID to a different one. You've basically renamed it, although Apple states that you can't rename an Apple ID, and thus the device is still associated. It will stay associated to your account until you release it via the Find My iPhone feature online or by calling Apple and have them do it as long as you can prove your identity. At least that's my understanding.

Thanks for your reply! I hope that is the case. If so, I will continue to monitor the phone from time-to-time to see if we get lucky. Oddly enough, a 2nd tier tech person at Apple who I spoke to is clueless about this and is supposed to be researching the answer. I have waited over a week to get an answer which is why I came to this forum. When I asked to speak to a manager, due to her inability to respond to our question, she told me there is no manager to speak to and that she was our last stop. Overall, I am very disappointed with Apple Customer Service.

Anyway, if anyone else can confirm your understanding D, that would be great! Thanks again.

Thanks for your reply! I hope that is the case. If so, I will continue to monitor the phone from time-to-time to see if we get lucky. Oddly enough, a 2nd tier tech person at Apple who I spoke to is clueless about this and is supposed to be researching the answer. I have waited over a week to get an answer which is why I came to this forum. When I asked to speak to a manager, due to her inability to respond to our question, she told me there is no manager to speak to and that she was our last stop. Overall, I am very disappointed with Apple Customer Service.

Anyway, if anyone else can confirm your understanding D, that would be great! Thanks again.

As a follow-up on this, I understand that the phone is probably forever connected to my son's Apple ID/account until it can legitimately be disconnected. More importantly at this point though would be, will Find My iPhone via the iCloud continue to track the location of his phone and be able to send the "lost phone message with phone number" to anyone who turns it on, considering the phone has the old login name and the iCloud/Find My Iphone now has the new login name.

Another thought I had was we could change the iCloud name back to the old name (email address), but it would have to have a different password as you cannot use a password on iCloud that you've used in the past year. The tech person I spoke to made it sound like that wouldn't work because the phone would have a different password and wouldn't log-in. I'm not sure that she really knows what happens and is merely guessing at this point. - - - As I mentioned in original post, my son's iPad with the old name was indeed being tracked by the iCloud/Find My Iphone with the new name.... So, I would love to hear from someone that knows what would really happen in this situation. Thanks very much!